WASHINGTON - The transplant was drawing near, and Kimberly Tracy knew she might die. She sat down to write her 2-year-old nephew a letter.

"I'm writing this letter to you now in case I can't tell you later," Tracy typed on her computer as she prepared to give him one of her kidneys. "Maybe something went wrong during the transplant or I became ill afterwards. ... All I know is that I wanted to tell you how much I love you."

She slipped the pages inside the folder with her will and her life insurance documents. Soon after, her healthy kidney was transplanted into her nephew's tiny, sick body.

Tracy, a 45-year-old nurse from Dayton, Ohio, survived, as did her nephew. But it was hardly the no-big-deal operation her doctors had promised. For months afterward, Tracy would vomit for no clear reason. She had abdominal cramps and shooting pelvic pain.

Yet complications like Tracy's are seldom reported or talked about, even as the number of living donors skyrockets. Increasingly, patients desperate for transplants are turning to families, friends, even acquaintances or co-workers.

Living donors now outnumber the traditional source of organs - cadavers - with 6,613 living donors last year, more than triple the number in 1990, according to the United Network for Organ Sharing.

Few donors die from the process, and there are no reliable statistics about surgical complications. But data suggest that as many as one in three liver donors, for example, face complications such as more surgery, hospitalization and extended recovery periods.

Transplant programs don't always provide donors with detailed information about the risks. And there's no central place donors can go for unbiased information - not just about obvious side effects, but about time lost from work, pain, discomfort and expenses.

Moreover, the organ donation system has its own built-in contradictions. A physician's guiding principle instructs do no harm, yet living donation removes an organ from a healthy person.

Donors form network

Most donors have no regrets, and many have only minimal pain.

"I used the morphine pump for the first day. Then I didn't need it anymore," said Ellen Souviney, 48, of Brunswick, Maine, who gave a kidney to her personal trainer. "I didn't even need aspirin after that."

Others are less satisfied. Tracy has begun an informal support network for living donors and is creating a Web site to help educate potential donors. She, too, has no regrets, but says: "My main concern is living organ donations will soon get a bad name if things aren't changed in the medical system."

Many in the field, including a federal advisory panel, are calling for fundamental change. Two ideas have emerged: a national registry to keep track of donors and their conditions after a transplant, and independent donor advocates at every transplant hospital who can dispassionately explain the risks.

Gregory Pence, a bioethicist at the University of Alabama, worries that living donation has become so common that family and friends feel intense pressure to donate if they are a medical match.

"You really have to ask, do people know what they're getting in for," he said. "No one really knows."

Moreover, each hospital has its own criteria for approving donors, with no standard guidelines.

In 1999, four Canadian hospitals refused to let a housekeeper donate a kidney to her ill boss, a wealthy Toronto developer, because of concerns that anyone donating to an employer might be under pressure to do so. But the developer turned to the Mayo Clinic in Rochester, Minn., which concluded the housekeeper was acting out of compassion and performed the surgery.

Death is one risk

Donor deaths are rare, though sometimes well publicized - like the reporter who died in New York in 2002 after giving a part of his liver to his brother. His death prompted a New York advisory committee to recommend what would be the strictest guidelines in the country for living donation.

Nationally, the transplant network has identified 28 donor deaths to date, including five that were definitively linked to the donation. And as of 2002, 56 kidney donors later needed a kidney transplant themselves.

Researchers at a transplant conference last month estimated that nearly one in three liver donors suffers a medical complication.

They found the typical donor is hospitalized for about 10 days, takes 21/2 months off work and needs another month for complete recovery.

Arielle Dove decided to donate a kidney to someone in need after the Sept. 11 terrorist attacks, and found a match through a living donor message board on the Internet. Today she's sick - regularly vomiting, lethargic and dizzy. She's also angry: The man who got her kidney reneged on a promise to cover her expenses not paid by his insurance.

"I volunteered to put my life on the line and I guess I've given up my good health for this and nobody seems to care," she said.